The present invention relates to systems for controlling the operation of cameras. More particularly, the invention relates to camera control systems which permit the selection of scanning of a sector of the total possible field of rotation of the camera and to camera control systems which change the mode of operation of the camera from a first mode of operation to a second mode of operation after the operation of the camera in the first mode of operation for a predetermined time interval.
Television surveillance systems have been used for many years to monitor remote areas from a central control location. These systems typically have a television camera rotatably driven to scan back and forth between predetermined angular limits to conduct surveillance within the field of view. These systems have the disadvantage of being limited to scanning the entire field of view defined by the predetermined angular limits. With these systems it is impossible to concentrate the scanning camera to a sector within the predetermined angular limits of rotation of the camera where it is desirable to concentrate surveillance. The presence of unusual activity in a sector contained within the angular limits of rotation or the variance of light conditions over a period of time within parts of the angular limits of rotation make it desirable to be able to selectively vary the field of scanning from the entire field defined by the predetermined angular limits to a sector contained therein.
Known television surveillance systems have employed various modes of operation in which the system continually operates in a single mode of operation until the operator changes the mode of operation. The continued operation of a surveillance system in a new mode of operation often occurs long after the condition which warranted the change in the previous mode of operation to the new mode has ceased to exist. The failure of these systems to revert to the previous mode of operation or to another mode of operation without operator intervention after the elapsing of a time interval is a serious disadvantage which often results in ineffective system operation and diminished surveillance capability.